Talked to a guy who owns a very reputable shop (I believe) in Charleston, SC yesterday about a new exhaust for my e92 335i. We discussed Dinan, and then he offered that he could (and has in the past for another customer) basically cut off the mufflers, fabricate stainless steel pipes, brackets, etc., and just run the pipes from wherever he cut off the mufflers out the back of the car. My car is registered in PA (an emissions state), and I asked him would the car still pass inspection? He said the first O2 sensor, cats, and second O2 sensor would remain untouched, and those are the parts that deal with the emissions. All the rest including the mufflers he proposes to cut off is just sound deadening material. He also said that because of the forced induction nature of the turbocharged engine, you don't need any backpressure to maintain peak HP, and the new exhaust would allow the engine to breathe better, weigh less, sound better, and all around be a great upgrade.

Although I think I understand the basics about my car, I am by no stretch an expert. So what do you guys think?

If you don't mind the constant drone than go for it. Personally, the drone would cause me to go insane. The muffler is a huge controller for sound and drone. $$ up for a nice exhaust that won't drive you crazy.